To Set Permission on USB Node "/Proc/Bus/Usb/bus-no/dev-no"

Hi all,
I am using CentOS 5 operating system. and trying to use a usb thermal printer.
This Printer works well if I log in as a root user, but I want to use it in non-root user mode. I have put this non root user in lp group also.
But No Success.

My printer uses usb port listed under /proc/bus/usb/bus-no/dev-no directory tree.
I want to set permission on it. [when I do it manually the printer starts working, but I don't want to do this in such way.] I need some automated way.

Also I found some techniques to set rules and permissions on usb port. but those techniques set the permission for /dev/bus/usb/bus-no/dev-no. and are of no use for me.